The Prince of Darkness' 25-year-old son has been dating model and aspiring actress Stelly for about four months -- and if the bride-to-be wants an idea of what kind of royal family she's getting into, she need only watch reruns of "The Osbournes," where Jack grew up in the public eye. One handy thing: He's already gotten rehab out of the way.

Kelly Osbourne congratulated Jack via Twitter on Friday, saying, "@MrJackO well i guess you're not my little brother anymore i'm so unbeliveably proud of the man you have become! im so happy for you & lisa!" Us Weekly confirmed the engagement Thursday.

Though Lisa is a model, as was Kelly's ex-fiancé, Luke Worrall, with luck the engaged thing will work out better for Jack than it did for Kelly. Though she may have dodged a bullet there, no?

Photo: Jack Osbourne with the family -- that'd be Kelly, left, Sharon and a picture of daddy Ozzy -- in Hollywood in August at a private preview of "God Bless Ozzy Osbourne," a documentary Jack directed. Credit: Mario Anzuoni / Reuters